An Event-Related Potential Study of Attention and Recognition Memory in Infants With Iron-Deficiency Anemia

Abstract

OBJECTIVES-The purpose of this work was to determine whether iron-deficiency anemia in infancy represents a risk factor for deficits in attention and memory development using event-related potentials.METHODS-Artifact-free event-related potential data were obtained at 9 and/or 12 months from 15 infants with iron-deficiency anemia and 19 who were iron sufficient during a test of the infant's ability to discriminate a highly familiar stimulus, the mother's face, from a stranger's face.RESULTS-A midlatency negative component associated with attention and a late-occurring positive slow wave associated with memory updating were identified at both ages in the irondeficiency anemia and iron-sufficient groups. Consistent with the age-appropriate pattern of development at 9 months, the iron-sufficient group showed a greater attentional response (negative component) to the mother and a greater updating of memory for the stranger (positive slow wave). This pattern of responses was not evident in the iron-deficiency anemia group until 12 months, suggesting a delay in cognitive development.CONCLUSIONS-These data suggest that iron-deficiency anemia adversely affects the allocation of neurophysiologic resources to attention and recognition memory during the processing of information about familiar and unfamiliar stimuli. This delay in cognitive development may reflect alterations in efficiency of central nervous system functions that seem related to early iron deficiency. Assessing specific neurocognitive functions with brain-based measures in human infants is challenging. Event-related potentials (ERPs) provide a noninvasive means for measuring transient changes in the brain's electrical activity in response to stimuli, allowing the evaluation of attention and memory in very young infants. ERP studies informed by animal models of diet-induced ID have shown impaired recognition memory in human infants with prenatal ID because of maternal diabetes during pregnancy. [7][8][9] The study reported here examined infant recognition memory in relation to IDA during its period of peak postnatal prevalence (6-24 months). This study was part of an integrated cross-species program project on the brain and behavior effects of early ID in human infants, nonhuman primate infants, and developing rodents. As part of a hypothesis-driven neurodevelopmental approach, the hippocampus and/ or related behaviors were assessed in all 3 species. Recognition memory was assessed using ERP in the human infant project.We hypothesized that postnatal IDA would alter attention and recognition memory because of the effect of iron on hippocampal development and function. To examine this hypothesis, we recorded ERPs in a procedure specifically focused on the infant's ability to recognize a highly familiar stimulus, the mother's face, and to discriminate the mother's face from a stranger's face. Two ERP components of particular interest have been identified in studies of infant memory: a midlatency negative component (NC) associated with attention and a l...

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Iron deficiency and infant motor development

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Issues in the Timing of Integrated Early Interventions: Contributions from Nutrition, Neuroscience, and Psychological Research

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